When Brenton Hollitt bought a $200 motorbike at a caravan park at Tennant Creek 20 years ago, he never expected it would lead him on a 3,000-kilometre trek back to the Northern Territory, years later.

The bike enthusiast took it to the police station to check it was not stolen and a local officer recognised the 1967 Honda 360 as having been the first motorcycle used by Northern Territory police.

When Mr Hollitt decided to move from the Top End to Adelaide, he took the motorcycle with him.

He has spent the past two decades restoring it and says it 'runs like a dream'.

"I've spent a lot of money doing it up, it's fantastic now," he said.

After a ceremony in Adelaide today, Mr Hollitt rode off north and will donate the bike to the Northern Territory Police Museum and Historical Society in Darwin.

I'll be sad to see it go, but it's going back to where it belongs

Brenton Hollitt

"It belongs in the Northern Territory, where it came from, it's their history and to a lot of people, the Northern Territory is a fairly young state (sic) and they don't sort of consider their history, being a young state, until it's too late," he said.

His ride from Adelaide will take him through Port Augusta, Alice Springs and Tennant Creek before he arrives in Darwin.

While in Alice Springs, Mr Hollitt will be joined by Scotty Mitchell, the policeman who recognised the bike's significance.

Mr Hollitt's ride also will raise money for prostate cancer research.

Of the bike, he said: "I'll be sad to see it go, but it's going back to where it belongs."